Several different designs of electric plug-in assemblies in general and coaxial cable plug-in assemblies in particular are known to the art.
At the high, and even higher, transmission speeds aforementioned, and when using coordinated contacts or contact devices in an electric plug-in assembly intended for coaxial cables, it is important that signal transmission can take place from a first coaxial cable to circuit board components such that the central conductors of the coaxial cables or the like obtain good contact with one another through the medium of the connecting devices of the plug-in assembly, although it is also important that the screening conductor of the coaxial cable is intact and connected directly to ground upstream of the system earth on the circuit board, also through the medium of the plug-in assembly, so that electromagnetic disturbances will be passed to ground before manifesting as disturbances on the system ground.
In the case of coaxial cable plug-in assemblies, measures have already been taken to ensure that good electrical contact is achieved between the central conductors and that good screening is also achieved through the plug-in assembly.
It is also known that when the transmission speed of the digitalized signals or current pulses, or the so-called bit rate, increases up towards 150 Mb/s and higher, the plug-in assemblies used become sensitive to occurrent disturbance voltages and that the transmitted current pulses can become distorted to such an extent as to make it difficult or impossible to understand the pulses.
Large voltages that occur on screening conductors have a highly negative effect in this respect.
It has been found practical to take measures for connecting the screening conductor directly to ground potential at a point located some distance upstream of the circuit board.
It is also known (U.S. Pat. No. 4,820,201) to connect the screening conductor of a coaxial cable to a metallic plug-in-assembly casing with the aid of a metal plate.
It is also known (U.S. Pat. No. 3,670,292) to use a foil having inner and outer resilient tabs for grounding purposes.